Mass balance of Trambau Glacier, Rolwaling region, Nepal Himalaya: in-situ observations, long-term reconstruction and mass-balance sensitivity

Abstract

We conducted a mass-balance study of debris-free Trambau Glacier in the Rolwaling region, Nepal Himalaya, which is accessible to 6000 m a.s.l., to better understand mass-balance processes and the effect of precipitation on these processes on high-elevation Himalayan glaciers. Continuous in situ meteorological and mass-balance observations that spanned the three melt seasons from May 2016 are reported. An energy- and mass-balance model is also applied to evaluate its performance and sensitivity to various climatic conditions. Glacier-wide mass balances ranging from −0.34 ± 0.38 m w.e. in 2016 to −0.82 ± 0.53 m w.e. in 2017/18 are obtained by combining the observations with model results for the areas above the highest stake. The estimated long-term glacier mass balance, which is reconstructed using the ERA-Interim data calibrated with in situ data, is −0.65 ± 0.39 m w.e. a−1 for the 1980–2018 period. A significant correlation with annual precipitation (r = 0.77, p < 0.001) is observed, whereas there is no discernible correlation with summer mean air temperature. The results indicate the continuous mass loss of Trambau Glacier over the last four decades, which contrasts with the neighbouring Mera Glacier in balance.

Reanalysing the 2007–19 glaciological mass-balance series of Mera Glacier, Nepal, Central Himalaya, using geodetic mass balance

“…a −1 , respectively (see Table S2 in section S4 of supplementary information for annual mass balances of these three glaciers). In May 2016 in the nearby Rolwaling region, immediately west of the Everest region, Sunako and others (2019) started to monitor the debris-free Trambau Glacier (23.34 km 2 , elevation range 5060–6690 m a.s.l., ~40 km from Mera Glacier) which is more than 4 times larger than Mera and located at similar elevations. They found a mean glacier-wide mass balance of −0.61 ± 0.39 m w.e.…”

Precipitation Characteristics and Moisture Source Regions on Mt. Everest in the Khumbu, Nepal

“…the glaciohydrological system in the HKH 11 and exerts a strong control over glacier mass balance, 12 but basic in situ measurements are lacking. For example, nearly all long-term observations of precipitation are from weather stations below 3,000 m, meaning that glacierized elevations have been largely unmonitored.…”

The Influence of Key Climate Variables on Mass Balance of Naimona'nyi Glacier on a North‐Facing Slope in the Western Himalayas

“…The mean mass balance for Mera and Rikha Samba glaciers during the 2011–2018 period is similar to our results for Naimona'nyi Glacier (Table 2). The relatively small mass balances for Mera and Rikha Samba glaciers may be related to high precipitation which compensated for mass loss from surface melt in the ablation season (Sherpa et al., 2017; Sunako et al., 2019). In summary, differences between the average mass balances for glaciers across the Himalayas over the last 10 years may be attributed to different local climate conditions, such as variations in the timing and amount of precipitation and T a during the ablation season.…”

“…Using the measured precipitation without correction, our energy and mass balance model could accurately reproduce the observed mass balance at different altitudes and at glacier‐wide scale during the 2011–2018 period. In addition, for glaciers in the Himalayas, some studies about the simulated mass balance by the glacier model does not correct precipitation using wind speed (Azam et al., 2014, 2020; Fujita & Nuimura, 2011; Sunako et al., 2019). Thus, we do not correct precipitation using wind speed.…”

“…For example, Sunako et al. (2019) looked at Trambau Glacier, on a south‐facing slope in the central Himalaya and found significant correlation between annual mass balance and annual precipitation, but no discernible correlation between annual mass balance and summer mean air temperature, while Mandal et al. (2020) found that interannual variability for the mass balance of Chhota Shigri Glacier, on a south‐facing slope in the western Himalayas, was driven by variations in air temperature during the ablation season (June to September).…”